04-01-2013, 01:55 PM
Influence of the expansion device on the performance of a heat pump using R-407 C under a range of charging condition
ABSTRACT
They investigated the effects of the expansion device on the performance of water to water heat pump using R-407 C. The heat pump applying the expansion devices of a capillary tube and an electronic expansion valve is tested by varying refrigerant charge amount from – 20 % to + 20 % of full charge and changing water temperature entering the condenser from 300C to 400C, while maintaining the water temperature entering evaporator at 250 C.
The result shows capacity and COP of R-407 C EEV system have little dependence on the refrigerant charge due to an optimum control of superheat by electronically adjusting the EEV opening. EEV system showed much higher system performance and reliability as compared with capillary tube system.